Why Should Life All Labor Be?

A. E. Housman, Last Poems, XI:

Yonder see the morning blink:
  The sun is up, and up must I,
To wash and dress and eat and drink
And look at things and talk and think
  And work, and God knows why.
 
Oh often have I washed and dressed
  And what's to show for all my pain?
Let me lie abed and rest:
Ten thousand times I've done my best
  And all's to do again.